Methods and systems for unlicensed mobile access realization in a media gateway

ABSTRACT

A media gateway comprising a plurality of network interface cards, at least one switch matrix, and a server module including at least one unlicensed mobile access module is provided. A method and computer-readable medium for activating an unlicensed mobile access channel for a mobile station in a network is provided. A media gateway receives a request to allocate an unlicensed mobile access termination. The request is received in response to at least one of a discovery registration by the mobile station and a handover request by the mobile station. The mobile station is serviced by at least one of a wireline network and a wireless network interfaced by the media gateway. The media gateway allocates the unlicensed mobile access termination. The termination has an identifier associated therewith. The media gateway receives at least one transmit parameter associated with the mobile station, and completes bearer set-up of the unlicensed mobile access channel according to the at least one transmit parameter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional patent applicationSer. No. 60/685,863, attorney docket number 34986.44, entitled, METHODSAND SYSTEMS FOR UNLICENSED MOBILE ACCESS (UMA) REALIZATION IN A MEDIAGATEWAY, filed May 31, 2005, by He, et al, the disclosure of which isincorporated herein by reference.

This application is related to commonly assigned U.S. ProvisionalApplication No. 60/611,221, entitled “media gateway FOR MULTIPLEWIRELINE AND WIRELESS FORMATS, COMPONENTS THEREOF, AND PROCESSESPERFORMED THEREIN,” filed on Sep. 18, 2004, the entirety of which ishereby incorporated by reference herein.

This application is also related to commonly assigned U.S. patentapplication Ser. No. 09/792,265, entitled “VOICE PACKET SWITCHING SYSTEMAND METHOD,” filed on Feb. 23, 2001, the entirety of which is herebyincorporated by reference herein.

This application is also related to commonly assigned U.S. patentapplication Ser. No. 11/121,626, entitled “APPARATUS AND METHODS FORPER-SESSION SWITCHING FOR MULTIPLE WIRELINE AND WIRELESS DATA TYPES,”filed on May 4, 2005, the entirety of which is hereby incorporated byreference herein.

BACKGROUND

Telecommunication carriers are increasingly deploying bundled ormulti-service packages to provide reduced access charges to increasecustomer retention. For example, the boom in digital subscriber linesubscriptions has led many carriers to bundle high bandwidth Internetservice with traditional voice services and/or wireless services.Already, carriers are feeling the strain of successfully upgradingexisting infrastructures to meet the high-bandwidth services beingdemanded by customers.

Transition networks are commonly utilized to provide customer access tovoice and data networks. An access network interfaces with voice anddata switches each respectively interfacing with, for example, a packetbackbone network and a public switched telephone network. Typically,various classes of voice switches are required within the transitionnetwork (e.g., class 4 switches for providing interexchange carrier(IXC) voice services and class 5 switches for providing end office voiceservices). Multiple media gateways are then required to interface with adata access switch.

Significant amounts of labor are expended to maintain and upgrade thetransition networks as new services become available. A move to unifiedaccess is clearly advantageous and promises to propel emergingtechnologies that are not easily implemented over current large scalenetworks, for example voice over internet protocol (VoIP), voice overDSL (VoDSL), UMTS and other wireless formats, time division multiplex(TDM), and asynchronous transfer mode (ATM), to a broader degree ofacceptance.

Unlicensed Mobile Access (UMA) technology provides access to GSM andGPRS mobile services over unlicensed spectrum technologies, such as WiFi(802.11) and Bluetooth. For example, by deploying UMA technology,service providers may enable subscribers to roam and handover betweencellular networks and public and private unlicensed wireless networksusing dual-mode mobile handsets. With UMA, subscribers may receive aconsistent user experience for their mobile voice and data services asthey transition between networks. Some of the purposes and potentialbenefits of UMA may include resolving the lack of radio frequency (RF)capacity in a wireless network, reaching subscribers at their homes inan advantageous manner relative to traditional wireless access, andreducing network and other operational and capital expenditures. As UMAgains a broader degree of acceptance, service providers may be able tooffer greater service distinction and differentiation, and networkcapacity may be gained through IP networks and unlicensed RF spectrum.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isemphasized that, in accordance with the standard practice in theindustry, various features are not drawn to scale. In fact, thedimensions of the various features may be arbitrarily increased orreduced for clarity of discussion.

FIG. 1 depicts a schematic view of an embodiment of at least a portionof apparatus and/or network architecture according to aspects of thepresent disclosure;

FIG. 2 depicts a schematic view of an embodiment of at least a portionof the apparatus and/or network architecture shown in FIG. 1;

FIG. 3A depicts a schematic view of an embodiment of at least a portionof a gateway apparatus according to aspects of the present disclosure;

FIG. 3B depicts a schematic view of one embodiment of a portion of thegateway apparatus shown in FIG. 3A;

FIG. 4 depicts an embodiment of a signaling exchange for a UMA trafficchannel assignment procedure between a media gateway controller, a mediagateway and a mobile station;

FIG. 5 depicts an embodiment of a signaling exchange of a UMA trafficchannel assignment failure procedure between a media gateway controller,a media gateway and a mobile station;

FIG. 6 depicts an embodiment of a signaling exchange of a UMA trafficchannel release procedure between a media gateway controller, a mediagateway, and a mobile station;

FIG. 7 depicts an embodiment of a signaling exchange of a media gatewayquality alert procedure between a media gateway controller, a mediagateway, and a mobile station; and

FIG. 8 is a schematic representation of an embodiment of a slidingwindow mechanism used to group the speech frame blocks for transmissionand retransmission of frame blocks.

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides manydifferent embodiments, or examples, for implementing different featuresof various embodiments. Specific examples of components and arrangementsare described below to simplify the present disclosure. These are, ofcourse, merely examples and are not intended to be limiting. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

FIG. 1 depicts a schematic view of at least a portion of an embodimentof a network 100 architecture according to aspects of the presentdisclosure. A gateway network 110 permits communications between aplurality of different types of networks, such as one or more licensedwireless networks 120, one or more wireline networks 130, one or moreUMA networks 140, and/or other networks. As employed herein, a networkmay refer to an entire network or to a network portion, a networkapplication, and/or network apparatus. Moreover, the UMA network 140 isnot limited within the scope of the present disclosure to UMA-exclusivenetworks. For example, network 140 may be a UMA network, a WLAN network,a Wi-Fi network, and/or combinations thereof, including combinationnetworks not directly supporting UMA (e.g., supporting WLAN, Wi-Fiand/or other protocols but not UMA). For the sake of simplicity, thesenetworks may be referred to herein as UMA networks. Nonetheless, thescope of the present disclosure is not limited to embodiments in whichnetwork 140 supports UMA, whether exclusively or in combination withother formats.

Examples of licensed wireless networks 120 include those supporting GSM,UMTS, and CDMA, including 2G and/or 3G technologies, among others. Thewireline network(s) 130 may be or include a public switched telephonenetwork (PSTN), among others supporting technologies based on TDM and/orother non-packet technology. UMA network(s) 140 may be or include thoseconforming at least in part to the specifications developed by the UMAParticipating Companies (“UMA Forum”), 3GPP, and/or others. Although notexplicitly depicted in FIG. 1, one or more other packet-based networks(e.g., the Internet) may also interface gateway network 110, such asthose supporting voice over Internet Protocol (VoIP), as well as one ormore other broadband networks, such as those supporting 802.11 (e.g.,WiFi) and/or 802.16 (e.g., WiMAX). One or more of the networks bridgedby gateway network 110 may also support voice over various otherprotocols, such as ATM.

One or more of the networks connected by gateway network 110, such asUMA network 140 in the embodiment shown in FIG. 1, may be connected togateway network 110 by one or more access networks 150. In a generalsense, such access networks 150 may perform various translation,conversion, transcoding and/or other processing, such as may facilitatecommunication between gateway network 110 and the various other networksconnected thereby.

Gateway network 110 may include one or more media gateways 115 a-115 c(collectively referred to as media gateways 115) and/or other apparatuswhich may be singularly or collectively employed to bridge two or moreof the wireline, wireless, UMA and/or other networks. In one embodiment,gateway network 110 may include only one media gateway, such as oneexample in which the gateway network 110 is primarily a single mediagateway and a number of interfaces to the various other networks.

The one or more media gateways 115 deployed in (or as) the gatewaynetwork 110 may convert data from a format, protocol, and/or typerequired for one network into another format, protocol, and/or typerequired for another network. Moreover, at least in some embodiments,this conversion may be performed on a per-session basis or a per-channelbasis. Each media gateway 115 a-115 c may be configured to transferaudio, video, fax and/or T.120 (real-time multi-point communications)data, among other data types, which the media gateways 115 may handlesimultaneously, including embodiments in which one or more of the mediagateways 115 is configured to send and receive both packet andnon-packet data. In one embodiment, at least one of the media gateways115 may be substantially similar to those described in U.S. patentapplication Ser. No. 11/121,626, entitled “APPARATUS AND METHODS FORPER-SESSION SWITCHING FOR MULTIPLE WIRELINE AND WIRELESS DATA TYPES,”filed on May 4, 2005.

In embodiments employing more than one media gateway 115 in gatewaynetwork 110, or those employing more than one gateway network 110, oneor more of the other networks may interface with more than one of themedia gateways 115 or gateway networks 110. For example, in theembodiment illustrated in FIG. 1, wireline network 130 is directlyconnected to two of media gateways 115 b and 115 c of gateway network110 (e.g., via one or more trunks, loops, carriers, and/or other copper,optical, or other transmission links). Similarly, where a network, suchas UMA network 140, is configured to communicate with gateway network110 via access network 150, access network 150 may be directly connectedto more than one of media gateways 115. Also, media gateways 115deployed in gateway network 110 may collectively be connected in acompletely meshed arrangement, although the scope of the presentdisclosure is not limited to such embodiments.

UMA network 140 includes one or more access devices 145 configured tofacilitate communication between user equipment (UE) 160, such as adual-mode mobile station (MS), and the corresponding access network 150,among other networks. For example, the one or more access devices 145may include one or more access points, routers, switches, and/or networkcontrollers, and/or devices for performing similar functions thereof,including those described in the UMA, WLAN, Wi-Fi and/or otherspecifications developed by the UMA Technology Participating Companies(“UMA Forum”), 3GPP, and/or others.

FIG. 2 depicts a schematic view of an embodiment of the networkarchitecture shown in FIG. 1 according to aspects of the presentdisclosure.

FIG. 2 depicts a schematic representation of an embodiment of a gatewaynetwork that may be implemented as a core network 210 having IPtransport capability. For example, core network 210 may include a numberof media gateways 215 a-215 c (collectively referred to herein as mediagateway 215) interconnected by IP transmission lines, such as byportions of the Internet. Alternatively, or additionally, loops, trunksand/or other physical data transmission media dedicated to theinterconnection of the media gateways 215 may be employed. Mediagateways 215 may also be substantially similar to the media gateways 115shown in FIG. 1. For example, one or more of media gateways 215 may be awireless media gateway having aspects similar to those described in U.S.patent application Ser. No. 11/121,626, entitled “APPARATUS AND METHODSFOR PER-SESSION SWITCHING FOR MULTIPLE WIRELINE AND WIRELESS DATATYPES,” filed on May 4, 2005. Intercommunication between the mediagateways 215 may be implemented via Nb-UP and AMR-over-Nb.

FIG. 2 also demonstrates that the licensed wireless networks 120 shownin FIG. 1 may include a radio access network (RAN), such as a GSM-EDGEradio access network (GERAN) 220 a. GERAN standards are defined by 3GPP,which are hereby incorporated by reference. GERAN is a higher-speed timedivision multiple access (TDMA) RAN defined by the EDGE TDMA standard.The original GSM TDMA radio technology is based upon GMSK modulation,whereas EDGE uses eight-way phase shift keying (8PSK). EDGE can sharespectrum and TDMA timeslots with GSM.

As also shown in FIG. 2, licensed wireless networks 120 shown in FIG. 1may be or include one or more networks 220 b operating under the GSMand/or UMTS standards, among others, and the wireline networks 130 shownin FIG. 1 may be or include one or more PSTN networks 230.Intercommunication between the licensed wireless network(s) 220 b andcorresponding media gateway(s) 215 may be implemented via adaptivemulti-rate (AMR), whereas intercommunication between the PSTN network(s)230 and corresponding media gateway(s) 215 may be implemented via TDM,or otherwise corresponding to aspects of the particular type of networkbridged by the core network 210.

FIG. 2 also depicts IP access network 250 as an example of accessnetworks 150 described above with regard to FIG. 1. Intercommunicationbetween IP access network(s) 250 and corresponding gateway(s) 215 may beimplemented, for example, via AMR over IP and/or UMA-Up. One or more ofnetworks 220 a/220 b may include one or more base transceiver stations(BTSS) 222 or radio network stations or towers, as well as one or morebase station controllers (BSCs) 224 or radio network controllers. Thenetwork architecture may also include one or more media gatewaycontrollers (MGCs), such as the MGCs 270 shown in FIG. 2, and/or orsimilar components or functions which may be employed for various callcontrol functions and may possibly be separated from the transport layer(media gateways). In one embodiment, one or more of the MGCs 270 may beone or more softswitches, including one or more wireless softswitches,and may interface and control one or more media gateways 215 a-215 c.

In one embodiment, one or more of the media gateways 115, 215 and one ormore MGCs 270 associated therewith may cooperate or otherwisecollectively function in a manner similar to the function of a UMAnetwork controller (UNC). For example, MGC 270 may perform UMA UP (UserPlane) CS (Circuit Switched) Domain signaling protocol, such as UMAdiscovery/registration, call processing, authentication, and handover,among other functions, and one or more of media gateways 115, 215 mayperform UMA UP CS bearer functions, such as AMR over RTP using RFC 3267framing, and interoperate with any other of the media gateway-supportedinterfaces (e.g., TDM, UMTS, Iu/Nb, and/or VoIP, among others). RFC3267is a real-time transport protocol (RTP) payload format used for AdaptiveMulti-Rate and Adaptive Multi-Rate Wideband (AMR-WB) encoded speechsignals. The payload format is designed to be able to interoperate withexisting AMR and AMR-WB transport formats on non-IP networks.

FIG. 3A depicts a schematic view of an embodiment of at least a portionof one embodiment of an architecture of a media gateway 315, such asmedia gateway 115 shown in FIG. 1 or media gateway 215 shown in FIG. 2.

As shown in FIG. 3A, media gateway 315 may include a number of voiceserver modules 310 a-310 c (collectively referred to herein as voiceserver modules 310) interfaced with a TDM switch matrix module 320 andan ATM, or other packet, switch matrix module 330. TDM switch matrixmodule 320 receives TDM communications from one or more TDM networks viaa number of TDM network interfaces (NI) 340 a-340 c (collectivelyreferred to as TDM network interfaces 340), and also sends TDMcommunications to the one or more TDM networks via TDM NIs 340, whethersuch TDM communications originate from a TDM network or otherwise.Packet switch matrix module 330 receives IP, ATM and possibly otherpacket-based communications from one or more packet-oriented networks.For example, packet switch matrix module 330 may receive, for example,Ethernet and/or packet over synchronous optical network (SONET)communications from one or more IP networks via a number of IP NIs 350a-350, and may also receive ATM communications from one or more ATMnetworks via a number of ATM NIs, such as ATM NI 360.

FIG. 3B depicts a schematic view of an embodiment of a portion of mediagateway 315 shown in FIG. 3A.

As shown in FIG. 3B, one or more of the media gateways may include oneor more voice server modules 310 a-310 b each having one or more digitalsignal processor (DSP) modules 370 a-370 d (collectively referred toherein as DSPs 370) or functions and one or more segmentation andreassembly (SAR) modules 380 a-380 d (collectively referred to as SARs380) or functions. DSPs 370 and SARs 380 may be configured tocommunicate, process, and convert data to and from a commonformat/protocol (e.g., high-level data link control (HDLC)). Forexample, DSPs 370 may convert between communications between pulse codemodulation (PCM) on the TDM switch matrix module 320 side and one ormore formats/protocols carried by HDLC on the SAR side. In theembodiment illustrated in FIG. 3B, HDLC is employed forAMR/RFC3267/RTP/TDM, although other embodiments are within the scope ofthe present disclosure. SARs 380 may be configured to perform thesegmentation, assembly and possibly other processing to transferAMR/RFC3267/RTP/TDM HDLC communications on the DSP side andAMR/RFC3267/RTP/UDP/IP/AAL5 communications on the ATM switch matrixmodule 330 side, although other embodiments are within the scope of thepresent disclosure.

The following discussion pertains to at least one embodiment of agateway, such as gateways 115, 215, and 315 shown in FIGS. 1-3B, forbridging various wireless, wireline and UMA networks described above.However, one or more aspects described below may not pertain to everyembodiment within the scope of the present disclosure.

A voice server module (VS or VSM) as described above may include aVS-UMA card which may be based on other VSM physical cards. One such VSMphysical card may have a plurality of DSPs or DSP cards, such as oneembodiment including four DSP daughter cards of a first configurationand one DSP daughter card of a second configuration, where the first andsecond DSP daughter card configurations may differ primarily in theirprogramming, if not also physically. For the sake of example, a DSPdaughter card of the first configuration may provide AMR over RTP withthe RFC 3267 framing functions. The DSPs of the VS-UMA card may beconfigured to perform RFC 3267 framing for AMR over RTP/IP mediastreams, at least in one embodiment. The VS-UMA card may, for example,support up to 1536 UMA terminations, e.g., 48 UMA channels per chip.

UMA-enabled media gateway 315 supports UMA interfaces between UMA accessnetwork and the core network performing the UMA UP (User Plane) bearerfunctions. The UMA interface may be a logical interface, such as a VoIPtrunk interface over a GigE NIC (Network Interface Card) associated withthe UMA VoIP profile. In one embodiment, no physical VS-UMA resourcesare allocated when the UMA interface is provisioned. The gateway mayallocate VS-UMA card resources when a call is attempted on the UMAinterface. VS-UMA resource allocation may be on a per-UMA-call basis.

Media gateway 315 may maintain the operational and/or administrativestates of the UMA interface. For example, media gateway 315 may set anoperational state to “enabled” after the successful provision of a VoIPsubgroup. An operational state (“enabled” or “disabled”) may be definedfor UMA interfaces. In some embodiments, however, there are no physicalconnections to be setup, such that the operational state of UMAinterfaces may always be “enabled” after the successful provisioningthereof. As another example, when a UMA interface's administrative stateis locked, the media gateway may tear down or terminate all existingVoIP calls on the UMA interface, and may reject any new VoIP calls onthe UMA interface. When a UMA interface's administrative state isshutdown, the media gateway may keep the existing calls on the UMAinterface, and may reject any new VoIP calls on the UMA interface.

For UMA terminations, such as VoIP terminations on a UMA interface,media gateway 315 may support extensible gateway control protocol (EGCP)call control using EGCP UMA receive (Rx), or local, and transmit (Tx),or remote, descriptors. Defining UMA descriptors allows differentiationof the UMA access VoIP call control from session initiation protocol(SIP) access and bearer independent call control (BICC) CS2 VoIP callcontrol, and can also add the flexibility to define new UMA call controlparameters, such as redundancy speech sample count, etc. The UMA accessVoIP call control through EGCP may not use the IPBCP protocol, as inBICC-CS2, or session description protocol (SDP), as in the SIP access.The EGCP UMA descriptors may minimize potential impacts to other VoIPfunctions supported on the media gateway.

UMA User Plane VoIP bearer setup may be made through a UMA trafficchannel assignment procedure. This procedure may be applicable to, forexample, the mobile-originated call, the mobile-terminated call, and/orthe handover from GERAN to UMA.

FIG. 4 depicts an embodiment of a signaling exchange for a UMA trafficchannel assignment procedure between a media gateway controller (MGC), amedia gateway (MGW) and a mobile station (MS).

According the example shown in FIG. 4, the MGC requests the mediagateway to allocate an ephemeral VoIP UMA termination at the start ofthe UMA traffic channel assignment procedure (step 410). The EGCP ADDcommand may include an EGCP stream descriptor (e.g., audio), a LocalControl descriptor (e.g., stream mode, tapping, etc.), an AvdRxdescriptor (e.g., echo, jitter buffer), and a UMA Rx descriptor (e.g.,codec type, codec ACS mode, RTP payload type, packetization time, and/orredundancy count).

The media gateway replies to the MGC with an ADD Response that includes,for example, its UMA termination ID associated with the UMA terminationand UMA Rx descriptor (e.g., IP address, RTP UDP port, and other UMA Rxdescriptor parameters) (step 412). The media gateway controller may alsosends a URR ACTIVATE CHANNEL request to the MS with, for example, themedia gateway's IP address, RTP UDP port, and the RTP payload type (step414).

The MS then begins to transmit an uplink RTP media stream (step 416),and sends a URR ACTIVATE CHANNEL ACK response to the MGC (step 418)with, for example, the MS RTP UDP port and packetization time.

Subsequently, the MGC sends a MODIFY command to the media gateway (step420) with, for example, UMA Tx descriptor parameters associated with theMS or transmission characteristics thereof, such as MS IP address, RTPUDP port, packetization time, and/or payload type, among others. Themedia gateway may then send a MODIFY Response (step 422) and a NOTIFY(step 424) to indicate the bearer setup success, and begins to transmita downlink RTP media stream (step 426). When the MGC sends a URRACTIVATE CHANNEL COMPLETE message to the MS (step 428), the UMA TrafficChannel Assignment procedure may be completed.

FIG. 5 depicts an embodiment of a signaling exchange of a UMA trafficchannel assignment failure procedure between an MGC, a media gateway andan MS.

According the example shown in FIG. 5, the MGC requests the mediagateway to allocate an ephemeral VoIP UMA termination at the start ofthe UMA traffic channel assignment procedure by transmitting an EGCP ADDcommand to the MGW (step 510). An EGCP ADD command may include a EGCPstream descriptor (audio), a Local Control descriptor (e.g., streammode, tapping), an AvdRx descriptor (e.g., echo), and a UMA Rxdescriptor (e.g., codec type, codec ACS mode, RTP payload type,packetization time, and/or redundancy count, among others).

The media gateway then sends an ADD Response with, for example, its UMAtermination ID and UMA Rx descriptor (e.g., the IP address, the RTP UDPport, and/or other UMA Rx descriptor parameters), among others to theMGC (step 512). The MGC then sends a URR ACTIVATE CHANNEL request to theMS with the media gateway's IP address, RTP UDP port, and/or RTP payloadtype (step 514).

In the event of channel assignment failure, the MS then sends a URRACTIVATE CHANNEL FAILURE response to the MGC (step 516) with, forexample, the RR Cause value, and the MGC sends a SUBTRACT command to themedia gateway (step 518). The media gateway then sends a SUBTRACTResponse to the MGC (step 520).

FIG. 6 depicts an embodiment of a signaling exchange of a UMA trafficchannel release procedure between the MGC, the media gateway, and theMS.

According to the example shown in FIG. 6, the MGC sends a SUBTRACTcommand with an EGCP Statistics descriptor (empty values) at the startof the UMA traffic channel release procedure (step 610). The MGC mayappend the statistics descriptor in order to receive the SUBTRACTresponse message with statistics.

The media gateway then sends a SUBTRACT Response with the collectedstatistics reported in the EGCP Statistics descriptor (step 612). Themedia gateway preferably only sends the SUBTRACT Response if theSUBTRACT command has the EGCP Statistics descriptor.

The MGC may then send a URR RELEASE request to the MS with an RR Causevalue (step 614), and the MS may send a URR RELEASE COMPLETE response(step 616) to the MGC thereby concluding the UMA Bearer channel releaseprocedure.

Returning again to FIG. 4, upon receiving an EGCP-Add command for a UMAtermination, the media gateway may expect and accept the following EGCPdescriptors from the MGC, among others: a local control descriptor, andAvdRx descriptor, and a UMA descriptor. The local control descriptor maydefine the stream mode, tapping, and the like. The AvdRx Descriptor maydefine echo control, network address translation (NAT) learning, sessiondescription protocol (SDP) tunneling, and the like. For the UMAapplication, echo control and jitter buffer fields may be used. TheAvdRx Descriptor may also include a maximum jitter buffer, which maps toan H.248 Network Package maximum jitter buffer, for example. Thedescriptor value may be specified in, for example, milliseconds. If thecontrolling MGC does not provide this value, the media gateway may useits internal-provisioned jitter buffer value in the VoIP trunk subgroupobject. The media gateway may expect this value to be configured in thecontrolling MGC database. The UMA descriptor may define all therequisite UMA receive (Rx) and transmit (Tx) control parameters.

The media gateway may define UMA Rx Data and Tx Data components withinthe UMA descriptor in the EGCP interface. UMA Rx Data defines local UMAtermination properties, while UMA Tx Data defines remote UMA terminationproperties. The UMA Rx and Tx descriptors may be defined similarly oridentically, possibly with one or more of the following parameters:codec, initial AMR rate, IP address, RTP UDP port, RTCP UDP port, frameredundancy count, threshold window, bad quality threshold, good qualitythreshold, packetization time, RTP payload type. The initial AMR ratemay indicate an initial AMR rate when a multi-rate AMR codec is used.The values may map to an AMR frame type. The IP Address may indicate theRTP stream's IP address (e.g., IPv4) in binary form. The RTP UDP portand the RTCP UDP port may indicate the RTP stream's payload RTP UDP portand the RTP stream's RTCP UDP port, respectively. For example, if theRTCP UDP port is zero (0) then the RTCP is disabled. The frameredundancy count may have a value selected from a pre-defined frameredundancy count value range, such as values of ‘0’, ‘1’, ‘2’. The mediagateway may accept all 3 values. In one embodiment, a frame redundancycount of ‘0’ indicates no frame redundancy, a frame redundancy count of‘1’ indicates single frame redundancy, and a frame redundancy count of‘2’ indicates double frame redundancy. The frame redundancy scheme maybe defined in, for example, the RFC 3267. The media gateway may expectthis value to be configured in the controlling MGC database.

The threshold window may comprise a time interval in, for example,seconds to measure the RTP stream quality. The minimum value may be 5seconds or another suitable value, and the maximum value may be 60seconds, for example. The media gateway may expect this value to beconfigured in the controlling MGC database.

The bad quality threshold may comprise a percentage (e.g., 0%-99%) ofthe quality loss. The media gateway may calculate this quality loss bymeasuring the packet loss, among other manners. When the quality loss ishigher than this value, the media gateway may notify the MGC of the badbearer quality. The MGC may then decide if handover to GERAN procedureneeds to be performed. The media gateway may expect this value to beconfigured in the controlling MGC database. The good quality thresholdmay comprise a percentage (e.g., 0%-99%) of the quality loss. The mediagateway may calculate this quality loss by measuring the packet loss.After the media gateway sends a bad quality notification to the MGC,when the quality loss is lower than this value, the media gateway maynotify the MGC of the good bearer quality. The MGC may decide if thehandover to GERAN procedure needs to be cancelled. The Good QualityThreshold value may be less than the Bad Quality Threshold value. Themedia gateway may expect this value to be configured in the controllingMGC database.

The packetization time may comprise a value that may map to a UMA SampleSize information element (1E) value. The values ‘20 ms’, ‘40 ms’, ‘60ms’, and ‘80 ms’ are examples which may be defined. The media gatewaymay expect this value to be configured in the controlling MGC database.If the controlling MGC does not provide this value or provides aninvalid value, the media gateway may use its internal-provisionedpacketization time in the VoIP trunk subgroup object.

The RTP payload type may comprise a value that may map to a UMA PayloadType information element (IE). The UMA may use dynamic RTP payload type.A value between 96 and 127, for example, may be expected and accepted bythe media gateway. The media gateway may expect this value to beconfigured in the controlling MGC database.

The media gateway preferably rejects the EGCP request under specifiedscenarios, such as if the controlling MGC passed down unexpected valuesin the UMA descriptor to the media gateway.

For a UMA termination using a FR-AMR codec, the VAD function (e.g.,silence suppression, comfort noise) may be enabled by default. Thisresults in the AMR SID being transmitted periodically, e.g., every 160ms, if the media gateway detects silence.

Upon receiving an EGCP-Subtract command for a UMA termination, e.g., asindicated at step 610 in FIG. 6, if the MGC appends an emptyEGCP-Statistics descriptor, then the media gateway may report RTPstatistics in the EGCP-Subtract response as depicted in step 612. SuchRTP statistics may be defined according to the H.248 Network Package(nt) and RTP package (rtp), and may include: duration, octets sent,octets received, packets sent, packets received, packet loss, jitter,delay, and/or other statistics. The duration value may comprise aduration, e.g., in seconds, of the time the UMA termination has been inthe call. The octets sent and received may comprise respective valuesthat specify the number of octets sent and received via the UMAtermination. In a similar manner, the packets sent and received valuesmay comprise respective values that specify the number of packets sentand received via the UMA termination. The packet loss may comprise thecurrent rate of packet loss on an RTP stream expressed as a percentagevalue. The jitter value may comprise the current value (e.g., inmilliseconds) of the inter-arrival jitter on an RTP stream if RTCP isenabled. Otherwise, zero (0) may be returned for the jitter value. TheDelay may comprise a current value of packet propagation delay expressedin RTP timestamp units (e.g., 125 μs) if the RTCP is enabled. Otherwise,the delay value may be set to zero (0).

Even without RTCP enabled, the media gateway may send a RTP streamquality alert to the MGC in order to assist the MGC in making handoverdecisions.

FIG. 7 depicts an embodiment of a signaling exchange of a media gatewayquality alert procedure between a controlling MGC, a media gateway andan MS.

According to the example shown in FIG. 7, the media gateway may monitorthe uplink RTP media stream during the normal UMA voice traffic. If thequality loss threshold is higher than the bad quality threshold, themedia gateway may notify the MGC with a “Bad Quality Alert” event (step710 a). The MGC then sends a URR UPLINK QUALITY INDICATION message witha Quality Indication: “Undetermined problem” (step 712 a) to the MS.This message may trigger the MS to start the handover procedure, e.g., ahandover to a licensed wireless network 120 shown in FIG. 1 or awireless network 220 a or 220 b shown in FIG. 2.

If the quality loss threshold is lower than the good quality threshold,the media gateway may notify the MGC with a “Good Quality Alert” event(step 710 b). The MGC then sends a URR UPLINK QUALITY INDICATION messagewith a Quality Indication: “Quality OK” (step 712 b). This message maytrigger the MS to cancel a handover procedure.

In the event that the quality loss threshold is higher than the badquality threshold, the MS may initiate a handover procedure, e.g., inresponse to receipt of the URR UPLINK QUALITY INDICATION message withthe Quality Indication “Undetermined problem” shown in step 712 a. Forexample, the MS may subsequently send a URR HANDOVER REQUIRED message tothe MGC (step 714 a), and the MGC may start the handover procedure onthe media gateway (step 716 a). If the media gateway grants the handoverrequest, the MGC may send a URR HANDOVER COMMAND message to the MS (step718 a).

The media gateway may generate the Bad Quality Alert notification, asindicated in step 710 a, if the RTP stream's quality loss is higher thanthe Bad Quality Threshold value specified in the UMA Rx descriptor inthe EGCP Command. The media gateway may generate the Good Quality Alertnotification, as indicated in step 710 b, if the RTP stream quality lossis lower than the Good Quality Threshold value specified in the UMA Rxdescriptor in the EGCP Command, and the media gateway already sent theBad Quality Alert notification.

For UMA terminations, the media gateway may support per-call echocancellation, possibly using the echo control parameters signaled by theMGC via the EGCP call control interface.

RFC 3267 defines the RTP payload format for AMR and AMR-WB codecs. Whencarrying FR-AMR codec information in UMA, one or more of the followingRFC 3267 RTP framing parameters may be used by the media gateway: Octetaligned, no frame CRCs, no robust sorting, no frame interleaving, singlechannel per session, mode-change period, mode-change neighbor, andmode-set. The mode-change period may be set to, for example, ‘2’ toindicate the mode may change every 2^(nd) speech frame.

With RFC 3267, the RTP payload begins with a Codec Mode Request (CMR)field, followed by a number of Table of Contents (ToC) entries, andspeech data representing one or more speech frame blocks. In octetsaligned mode, the CMR and ToC fields are padded to an octet. A frametype index (FT) and/or a frame quality indicator (Q) may also beincluded.

The CMR field may be used for rate adaptation to indicate a codec moderequest sent to the speech encoder at the site of the receiver of thepayload. For example, the value of the CMR field may be set to the FTindex of the corresponding speech mode being requested. In oneembodiment, the FT index may be 0-7 for FR-AMR, and another value (e.g.,15) may indicate that no mode request is present. In another embodiment,however, the media gateway may not support AMR rate adaptation, such aswhere only one rate is used.

The FT index may be used to indicate either the AMR or AMR-WB speechcoding mode or comfort noise (SID) mode of the corresponding framecarried in the payload. For example, in the case of AMR speech, a valueof FT=7 may indicate that a frame carries AMR 12.2K samples.

The frame quality indicator Q may be set to a specific value (e.g.,zero) to indicate that the corresponding frame is severely damaged,where Q might otherwise retain a different set value (e.g., one) toindicate a good frame. However, in one embodiment, the media gateway mayalways set the frame quality indicator Q to the value corresponding tothe “good frame” indication when generating the AMR over RTP frames,ignore the frame quality indicator Q (whether they indicate bad or goodframe quality), and always decode the AMR speech frame.

The RFC 3267 payload format also supports forward error correction(FEC), frame interleaving and/or other means which may, among otherpurposes, increase robustness against packet loss. However, frameinterleaving is not used in the UMA network, and in some embodiments themedia gateway does not support the frame interleaving redundancy scheme.

Nonetheless, the media gateway may utilize a scheme of repetition ofpreviously sent data, as required by the UMA network and specified inRFC 3267, to achieve the FEC. This may be implemented by retransmissionof previously transmitted frame-blocks together with the currentframe-block(s). This may be performed through using a sliding window togroup the speech frame-blocks to send in each payload.

FIG. 8 is a schematic representation of an embodiment of a slidingwindow mechanism used to group the speech frame blocks for transmissionand retransmission of frame blocks.

Here, f(n−2) . . . f(n+4) denotes a sequence of AMR speech frame-blocks810 a-810 g and p(n−1) . . . p(n+4) denotes a sequence of payloadpackets 820 a-820 f. According to the example shown in FIG. 8, eachframe-block is retransmitted once (single redundancy, n=1) in thefollowing RTP payload packet. For example, frame blocks 810 a-810 b areincluded in the payload packet 820 a. Frame block 810 b (along withframe block 810 c) are then included in the following payload packet 820b. The use of this approach may not require signaling at the sessionsetup. Thus, the speech sender may choose to use this scheme withoutconsulting the receiver. The media gateway DSP receiver may receivemultiple copies or versions (possibly encoded with different modes) of aframe for a certain timestamp if no packet is lost. In one embodiment,however, only multiple same 12.2K AMR rate or AMR SID speech frames maybe received in the same RTP payload.

The media gateway may also support the decoding of the RTP payload thatutilizes the sliding window FEC scheme with zero, single and double(n=0/1/2) when receiving the UMA RTP payload stream. The sender may beresponsible for selecting an appropriate amount of redundancy based onfeedback about the RTP stream quality. In one embodiment, the redundancycount may be pre-provisioned in the MGC database, and may be passed downthrough the EGCP interface parameter frame redundancy count.

The media gateway may also support the encoding of the RTP payload thatutilizes the sliding window FEC (Forward Error Correction) scheme withzero, single and double (n=0/1/2) when sending the UMA RTP payloadstream. In order to enable downlink quality measurements in the MS, theUMA specification requires the media gateway should send at least oneRTP frame each 480 ms. In order to enable uplink quality measurements inthe media gateway, the UMA specification requires the MS to send atleast one RTP frame each 480 ms.

During active voice transmission, the media gateway may generate the RTPand AMR speech frame per the packetization time specified in the EGCPinterface. In one embodiment, however, only one packetization time maybe supported (e.g., 20 ms), such the media gateway may generate the RTPand the AMR 12.2K speech frame at a single, predetermined rate. If thereis no active voice, the media gateway may generate the RTP and the AMRSID at a lower predetermined rate, such as every 160 ms (per FR-AMRspecification).

An IP Differential Services (DiffServ) Framework can utilize the IPHeader Type of Service (TOS) bits to support different Classes ofServices (CoS). COS Marking can ensure preferential treatment of VoIPtraffic over other data traffic in an IP network. The media gateway maysupport the marking of DSCP (Diff Serv Code Point) in the RTP/UDPpacket. The DSCP value may be provisioned through the UMA interface onthe media gateway.

The media gateway may support calls to and from one or more UMAinterfaces where, for example, the other call legs can be on TDM or UMAinterfaces supported by the media gateway. Transcoding may be performedwhen, for example, it is required for the interworking between the twocall legs, such as between a UMA termination and a TDM or any othernon-UMA terminations in the same call context. Thus, transcoding mayeven be necessary (or desired) for UMA-to-UMA calls. In one embodiment,however, UMA-to-UMA and Nb/IuUP-to-UMA interworking (e.g., calls) mayoccur without transcoding. In general, however, at least someembodiments of the media gateway support each of the following handoverscenarios: TDM to TDM; TDM to UMA; UMA to TDM; and UMA to UMA. The mediagateway may also support the CTM (Cellular Text Modem) capabilities on aUMA termination.

Existing lawful intercept (CALEA) procedures may also be supported forUMA terminations. For example, the intercepted stream may provide PCMsamples, for example, after decoding the AMR stream.

The existing connections that involve UMA terminations may be preservedupon a CM hard/soft switchover, an SM hard/soft switchover, an AIhard/soft switchover, a PM hard/soft switchover, and/or a VSM hard/softswitchover. Mid-call codec negotiation may also be supported, but maynot in other embodiments.

In view of all of the above, it should be understood that the presentdisclosure introduces UMA access that inter-works with GERAN TDM access,including where a media gateway provides handover support between GERANaccess and UMA access. The present disclosure also provides for UMAaccess that alternatively or additionally inter-works with NbUP over IPtrunking features.

The foregoing has outlined features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions andalterations herein without departing from the spirit and scope of thepresent disclosure.

1. A media gateway, comprising: a plurality of network interface cards; at least one switch matrix; and a server module including at least one unlicensed mobile access module.
 2. The media gateway of claim 1, wherein the plurality of network interface cards include one or more wireline network interface cards and one or more wireless network interface cards.
 3. The media gateway of claim 2, wherein the one or more wireline network interface cards comprise one or more time division multiplex network interface cards.
 4. The media gateway of claim 1, wherein the plurality of network interface cards comprise one or more packet network interface cards.
 5. The media gateway of claim 4, wherein the one or more packet network interface cards comprise at least one of an Internet protocol network interface card and a asynchronous transfer mode network interface card.
 6. The media gateway of claim 1, wherein the at least one switching matrix comprises at least one time division multiplex switch matrix and at least one packet switch matrix.
 7. The media gateway of claim 1, wherein the server module comprises a voice server module.
 8. The media gateway of claim 1, wherein the unlicensed mobile access module comprises one or more digital signal processors adapted to frame adaptive multi-rate voice data on a real-time transport protocol media stream.
 9. A method of activating an unlicensed mobile access channel for a mobile station in a network, comprising: receiving, by a media gateway, a request to allocate an unlicensed mobile access termination, wherein the request is received in response to at least one of a discovery registration by the mobile station and a handover request by the mobile station, and wherein the mobile station is serviced by at least one of a wireline network and a wireless network interfaced by the media gateway; allocating, by the media gateway, the unlicensed mobile access termination, wherein the termination has an identifier associated therewith; receiving, by the media gateway, at least one transmit parameter associated with the mobile station; and completing bearer set-up of the unlicensed mobile access channel according to the at least one transmit parameter.
 10. The method of claim 9, wherein the at least one transmit parameter comprises a unlicensed mobile access transmit descriptor.
 11. The method of claim 9, wherein the request includes an unlicensed mobile access receive descriptor.
 12. The method of claim 9, further comprising transmitting, by the media gateway, a bearer success notification in response to completing bearer set-up.
 13. The method of claim 12, further comprising: notifying the mobile station of completion of the bearer set-up; and engaging, by the mobile station, in communications on the channel.
 14. The method of claim 9, further comprising invoking, by the media gateway, a handover procedure that transfers communications of the mobile station from a cellular network to an unlicensed mobile access network, wherein the media gateway interfaces with the cellular network and the unlicensed mobile access network.
 15. The method of claim 9, further comprising transferring, on the channel, data between the mobile station and the media gateway, wherein the media gateway transfers the data on at least one of a public switched telephone network, a packet network, and a cellular network.
 16. A computer-readable medium having computer-executable instructions for execution by a processing system, the computer-executable instructions for activating an unlicensed mobile access channel for a mobile station in a network, comprising: instructions that receive, by a media gateway, a request to allocate an unlicensed mobile access termination, wherein the request is received in response to at least one of a discovery registration by the mobile station and a handover request by the mobile station, and wherein the mobile station is serviced by at least one of a wireline network and a wireless network interfaced by the media gateway; instructions that allocate, by the media gateway, the unlicensed mobile access termination, wherein the termination has an identifier associated therewith; instructions that receive, by the media gateway, at least one transmit parameter associated with the mobile station; and instructions that complete bearer set-up of the unlicensed mobile access channel according to the at least one transmit parameter.
 17. The computer-readable medium of claim 16, wherein the at least one transmit parameter comprises a unlicensed mobile access transmit descriptor.
 18. The computer-readable medium of claim 16, wherein the request includes an unlicensed mobile access receive descriptor.
 19. The computer-readable medium of claim 16, further comprising instructions that invoke, by the media gateway, a handover procedure that transfers communications of the mobile station from a cellular network to an unlicensed mobile access network, wherein the media gateway interfaces with the cellular network and the unlicensed mobile access network.
 20. The computer-readable medium of claim 16, further comprising instructions that transfer, on the channel, data between the mobile station and the media gateway, wherein the media gateway transfers the data on at least one of a public switched telephone network, a packet network, and a cellular network. 